This invention relates to the field of printing ribbon devices and in particular to devices for replenishing marking fluid to a ribbon.
With the recent dramatic growth in the use of automatic printing equipment of various types, including typewriters, computer print-out devices and similar devices, there has been a parallel increased demand for improved printing ribbon equipment. Numerous advances have been made as evidenced by the large number of patents issuing in this field. Considerable technical progress has been made in extending the useful life of a printing ribbon. And, improved printing ribbon cartridges have been developed for the purpose of providing convenient means for changing of printing ribbons. However, there remains a significant need for improvement in printing ribbon devices.
Reinking of a printing ribbon, such as an endless ribbon in a cartridge, has been considered as one means of extending the useful life of the ribbon. Ribbon reinking, however, can lead to difficult technical problems and substantial inconvenience for printing equipment operators. One such technical problem relates to over-inking of a ribbon already having sufficient ink for effective printing. Another technical problem relates to unevenness in print darkness upon sudden actuation of a reinking device after an initial period of inactivity. Numerous other related problems are known to those skilled in the art.
This invention addresses each of the aforementioned problems. Broadly described, the invention is a device for replenishing marking fluid to a printing ribbon, characterized by a source of additional marking fluid adjacent the ribbon and wear-actuated means to cause contact of the marking fluid with the ribbon. The invention also includes several specific, advantageous features which will be described in detail.
This invention provides an automatic, delayed and gradual replenishment of marking fluid to a printing ribbon. Such replenishment begins or is accelerated after an initial period of ribbon use and may continue on an increasing basis as use of the ribbon continues.